Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 50592 — Truesdale, IA

ZIP code 50592 (Truesdale, Buena Vista County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is April 25 and the first fall frost October 13.

Where ZIP 50592 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone5a−20 to −15 °F

Coldest night−28.9 to −26.1 °C

Last frostApr 25

First frostOct 13

2012 zone5a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Truesdale, IA…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Truesdale, IA

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 25median — 50% chance of a later frost

Safe for tender plantsMay 7only 10% chance of frost after

First fall frostOctober 13median — 10% chance by Oct 1

Growing season170 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 15 and returns around October 23.

From the NOAA station Storm Lake, IA — 6 miles away, elevation 1,444 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 50592

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 14 – Mar 28

SpinachSow outdoors · Mar 14 – Apr 4

Broccoli, cabbageStart indoors · Feb 14 – Feb 28

Broccoli, cabbageTransplant · Apr 4 – Apr 18

Onion setsPlant outdoors · Mar 28 – Apr 11

PotatoesPlant outdoors · Apr 4 – Apr 18

LettuceSow outdoors · Mar 28 – Apr 11

Carrots, beetsSow outdoors · Apr 4 – Apr 18

TomatoesStart indoors · Feb 28 – Mar 14

TomatoesTransplant · May 2 – May 16

Peppers, eggplantStart indoors · Feb 14 – Feb 28

Peppers, eggplantTransplant · May 9 – May 23

BeansSow outdoors · May 2 – May 16

Sweet cornSow outdoors · May 2 – May 16

Cucumbers, squashSow outdoors · May 2 – May 16

Fall lettuce, spinachSow outdoors · Aug 18 – Sep 1

GarlicPlant cloves · Sep 29 – Nov 3

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 25) and first fall frost (Oct 13) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 50592 came on Mar 25 — 16 days earlier than the 1991–2020 average (Apr 10).

average
Apr 102026
Mar 25

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 5a in Iowa

461 plants native to the lower 48 states, recorded in Iowa, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Truesdale, IA.

Soil in Truesdale, IA

The soil mapped at the center of ZIP 50592 is Clarion — loam, moderately well drained.

TextureLoama good balance for most vegetables

pH6.2slightly acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter3.5%moderate

Hydrologic groupCwater soaks in slowly

Farmland classprime farmlandUSDA classification

Map unit: Clarion loam, 2 to 6 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 50592; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Truesdale, IA

Summer high82 °Faverage high, July

Winter low9 °Faverage low, January

Hot days10days a year at 90 °F or more

Freezing nights151nights a year at 32 °F or less

Growing degree days2,908base 50 °F — the season’s usable heat

Longest day15 h 20 mindaylight on June 21

Shortest day9 h 02 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation33.8 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Storm Lake, IA (6 mi away); precipitation: Storm Lake, IA (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

505765a

Rembrandt, IA · 5 mi

505885a

Storm Lake, IA · 5 mi

510025a

Alta, IA · 7 mi

505105a

Albert City, IA · 10 mi

Sioux Rapids, IA · 13 mi

Iowa planting zones →

Questions about 50592

What planting zone is ZIP code 50592?

ZIP code 50592 (Truesdale, IA) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Truesdale, IA?

The median last spring frost (32 °F) near 50592 is April 25; after May 7 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Storm Lake station.

When is the first frost in Truesdale, IA?

The median first fall frost near 50592 is October 13, giving a median frost-free growing season of 170 days.

When should I plant tomatoes in 50592?

Start tomato seeds indoors around Feb 28 – Mar 14 and set transplants outside around May 2 – May 16, one to three weeks after the median last frost.

How much rain and snow does 50592 get?

About 33.8 inches of precipitation a year (NOAA 1991–2020 normals, Storm Lake station).

How hot do summers get in Truesdale, IA?

The average high peaks at 82 °F in July, with about 10 days a year at 90 °F or more.

What kind of soil does 50592 have?

The USDA soil survey maps Clarion at the center of ZIP 50592: loam, moderately well drained, pH about 6.2 (slightly acidic).

Did spring come early in Truesdale, IA in 2026?

Spring leaf-out near 50592 came on Mar 25 in 2026, 16 days earlier than the 1991–2020 average (Apr 10), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Truesdale, IA?

Long-day onions: the longest day near 50592 is 15 h 20 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).